(1) Field of the Invention
The present invention relates to vehicular running control apparatus and vehicular running control method, utilizing a car navigation system and an autonomous running control system. The present invention more particularly relates to the vehicular running control apparatus and vehicular running control method which can achieve an appropriate running (or traveling) control for the vehicle in a case where a curved road state located in front of a running road on which the vehicle is running obtained by a car navigation system is different from an actual situation of the curved road.
(2) Description of Related Art
As a recent trend, car navigation systems mounted in many automotive vehicles and have functions to detect a present running position of the vehicle using a road map information, a GPS (Global Positioning System) function, and so forth and to calculate a running route from the detected present position to a final destination position to guide the vehicle. In addition, many vehicular running control techniques to perform a vehicular vehicle speed control and so forth compositely of a host vehicle (the host vehicle is used in place of the vehicle in which the vehicular running control technique described herein is adopted) utilizing the functions of the car navigation system have been proposed.
A Japanese Patent Application First Publication (tokkai) No. Heisei 6-36187 published on Feb. 10, 1994 exemplifies a previously proposed vehicular running control apparatus in which, when a curved road is detected in front of the running road on which the host vehicle is running, a target vehicle speed of the host vehicle is calculated when the host vehicle is passed through the curved road from a dimension and so forth of the curved road and a target deceleration to obtain the target vehicle speed is calculated on a basis of the calculated target vehicle speed and an output of a vehicle speed detecting section. Then, when determining that the host vehicle speed is in an over-speed state, the host vehicle is controlled to be decelerated immediately before the host vehicle enters the curved road, the host vehicle is in a cruise (speed) control at a safe speed in a midway through the curved road, and the host vehicle speed is again controlled to be accelerated to a predetermined speed when the host vehicle is to run at an end (exit) of the curved road. Thus, the host vehicle can pass the curved road at an optimum speed.